Wireless transmitter

Abstract

A wireless transmitter includes: a plurality of transmission antennas; a phase rotating unit which adds phase rotation to signals which are respectively input to the plurality of transmission antennas; and a reception unit which receives information on phase control of arbitrary antennas among the plurality of transmission antennas from another party of communication, wherein the phrase rotating unit adds first phase rotation for controlling the maximum delay time between the plurality of transmission antennas depending on whether transmission is performed using frequency diversity or transmission is performed using multi-user diversity and second phase rotation for controlling the phases of the arbitrary antennas among the plurality of transmission antennas based on the information.

The invention claimed is: 
     
       1. A wireless transmitter comprising:
 a plurality of transmission antennas; 
 a phase rotating unit configured to add a phase rotation to signals which are respectively input to the plurality of transmission antennas; and 
 a reception unit configured to receive information on a phase control of arbitrary antennas among the plurality of transmission antennas from another party of communication, 
 wherein the phase rotating unit adds a first phase rotation for controlling a maximum delay time between the plurality of transmission antennas depending on whether transmission is performed using a frequency diversity or a multi-user diversity and a second phase rotation for controlling phases of the arbitrary antennas among the plurality of transmission antennas based on the information. 
 
     
     
       2. The wireless transmitter as recited in  claim 1 , wherein the wireless transmitter is used in a transmission system in which scheduling of users is performed on a per-chunk basis where a region defined in a frequency domain and in a time domain is divided into chunks in the frequency domain and in the time domain, and
 in the case in which the frequency bandwidth of the chunk is Fc, the phase rotating unit adds the first phase rotation so that the maximum delay time between the plurality of transmission antennas is set to either a predetermined first value which is smaller than 1/Fc or a predetermined second value which is larger than 1/Fc. 
 
     
     
       3. The wireless transmitter as recited in  claim 2 , wherein the first value is zero. 
     
     
       4. The wireless transmitter as recited in  claim 1 , wherein a phase rotation amount added by the second phase rotation is a predetermined value. 
     
     
       5. The wireless transmitter as recited in  claim 4 , wherein a plurality of values are prepared for the predetermined value, and the information includes information for designating a value from among the plurality of values. 
     
     
       6. The wireless transmitter as recited in  claim 1 , wherein the information includes information for designating an antenna to which the second phase rotation is added. 
     
     
       7. The wireless transmitter as recited in  claim 1 , wherein the information includes information indicating a phase rotation amount of the second phase rotation which is added to the arbitrary antennas. 
     
     
       8. The wireless transmitter as recited in  claim 1 , further comprising a transmission unit configured to transmit pilot channels corresponding to the plurality of transmission antennas which are orthogonal to each other from the plurality of transmission antennas, respectively. 
     
     
       9. The wireless transmitter as recited in  claim 8 , wherein each of the orthogonal pilot channels is generated by the multiplication of an orthogonal code. 
     
     
       10. The wireless transmitter as recited in  claim 1 , wherein the phase rotating unit adds no phase rotation to a pilot channel. 
     
     
       11. The wireless transmitter as recited in  claim 1 , wherein the phase rotating unit does not add the first phase rotation to a pilot channel.